Field of the Invention
The present invention relates to eyewear with time shared viewing.
Background Art
Images may be generated for display in various forms. For instance, television (TV) is a widely used telecommunication medium for transmitting and displaying images in monochromatic (“black and white”) or color form. Conventionally, images are provided in analog form and are displayed by display devices in two-dimensions. More recently, images are being provided in digital form for display in two-dimensions on display devices having improved resolution (e.g., “high definition” or “HD”). Even more recently, images capable of being displayed in three-dimensions are being generated.
Conventional displays that produce two-dimensional views (i.e., 2D displays) may be used with a variety of active and passive eyewear to achieve three-dimensional image viewing functionality. Specifically, various types of glasses have been developed that may be worn by viewers to create a three-dimensional effect when viewing a conventional 2D display. One example of such types of glasses include those that utilize color filters to view 2D “anaglyph” video produced on conventional 2D displays. In such case, left eye lenses and right eye lenses receive a corresponding color filter such as red and green or red and cyan. Viewing anaglyph video through such glasses causes each eye to receive differing video. For instance, a left eye covered by a red filtering lens will cause a brain to perceive red as white and cyan as black. Similarly, a right eye covered by a cyan filtering lens will cause the brain to perceive cyan as white and red as black. Thus, with appropriately constructed anaglyph video and such glasses, a conventional display (or screen) can provide a three-dimensional effect.
Other types of passive eyewear include those employing polarization. For example, two polarizing lenses can be placed in a pair of glasses to cover the left and right eyes of a viewer. A first of such polarizing lenses can be placed within the glasses assembly at a polarizing orientation that differs from that of the other polarizing lens. Dual video projection sources, each with a different polarization orientation, can be used to produce a single 2D video on a screen. Such dual source video can then produce a three-dimensional viewing effect for a user wearing such polarized glasses. With linear polarization, a first projection at perhaps a vertical orientation would pass a similarly oriented left eye lens, while a second projection at a horizontal orientation would pass a similarly oriented right eye lens but not vice versa. With circular polarization, a clockwise polarized video projection would be passed by a clockwise polarized left lens while a counter-clockwise polarized right lens would be at least substantially blocked. In such approaches, it can be appreciated that substantially independent video can be received by each of a viewer's eyes.
With either type of passive eyewear (polarizing or color filtering), the lenses of the glasses pass two-dimensional images or video of differing perspective to a viewer's left and right eyes. The images (or video) are combined in the visual center of the brain of the viewer to be perceived as having three-dimensions.
Another approach for accomplishing three-dimensional perception in association with a 2D display involves active eyewear. For instance, synchronized left eye, right eye LC (liquid crystal) shutter glasses may be worn by a viewer for viewing a conventional two-dimensional display to create a three-dimensional viewing illusion. Each lens of the LC shutter glasses acts as an independently controllable LC shutter which can be switched between a mostly transparent state and a mostly blocking state. For the display, often at double the normal frame rate, a sequence of frames (video) is produced with frames that alternate between those intended for the left eye and those intended for the right eye. The LC shutter glasses operate so as to allow left eye intended frames to pass to the left eye while blocking such frames from the right eye, and vice versa. The glasses accomplish this by alternating between a left eye viewing configuration (left lens in a transparent state; right lens in a blocking state) and a right eye viewing configuration (right lens in a transparent state; left lens in a blocking state). At the same time and in synchrony, the display alternately displays left eye, right eye two-dimensional frame images, each such image having a corresponding left eye and right eye perspective using a technique called alternate-frame sequencing. Accordingly, images of a first perspective are passed to the viewer's left eye, and images of a second perspective are passed to the viewer's right eye to create the three-dimensional viewing illusion.
As with passive eyewear, multiple viewers can simultaneously view alternately displayed images that are provided by a 2D display by wearing respective LC shutter glasses.